Electronic impulse generator



Aug. 11, 1953 c. F. RENCH ELECTRONIC IMPULSE GENERATOR Original Filed Dec. 17, 1949 2 Sheets-Sheet 1 Nu. n

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Aug. 11, 1953 Original Filed Dgc.

INVENTOR CARL F. RENCH BY HIS ATTORNEYS Patented Aug. 11, 1953 ELECTRONIC IMPULSE GENERATOR Carl F. Bench, Troy, Ohio, assignor to The National CashRegister Company, Dayton, Ohio, a corporation of Maryland Original application December 17, 1949, Serial-No. 133,540, now Patent No. 2,591,007, dated April 1, 1952. Divided and this application March 14, 1951,*Serial No. 215,483

12 Claims.

This invention relates to a novel impulse generating apparatus and is a division of application Serial No. 133,540, which was filed on December 17, 1949, and which issued on April 1, 1952, as Patent No. 2,591,007.

The novel impulsegenerator is of a type which is capable of efi'ecting entries simultaneously in a plurality of denominational ordersof an accumulator. The impulse generator utilizes a plurality of .tubes, which are common to a plurality of denominational orders, for producing impulse trainscorresponding to thedigits 1 to 9 and containing corresponding numbers of impulses. These impulse trains, which are available to the pluralityof denominational orders, may be selectively switched to any one or more denominationaloutput conductors of the impulse generator by corresponding denominational digit-selecting means.

The plurality of tubes of the impulse generator includes an oscillator-controlled means for producing driving impulses a chain of tubes containlng a start tube and a priming tube for each of the digits 1 to-9, an impulse-trainproducing tube for each of the priming tubes and a transfer-cheating impulse-generating tube.

The priming tubes are driven by the driving impulses, once the start tube has been-rendered conducting, and will become conducting one after another'in sequence, beginning with the 9 tube and ending with the "1 tube. As each priming tube becomes conducting, it conditions a related impulse-train-producing tube also to respond to the driving impulses and produce an impulse train containing the number of impulses corresponding to the value of the priming tube. As soon as the impulse trains have been produced, the start tube and the priming tubes are returned to their non-conducting status and made ready for another amount-entering operation.

The impulse-train-tube circuit provides a low impedance source .for the impulses which is capabio of producing extremely strong impulses, so that theirquality will not be impaired and they will be able to produce satisfactory operation the accumulator even though the impulses are switched simultaneously to a plurality of denominational output'conductors to causeentries to be madein corresponding orders of the accumulator. This circuit also minimizes cross-talk or inter ference effects between conductors forming the output circuits.

The oscillatorof the impulse generator '5 also used to control a further impulse-generating means .to provide tens-transfer-cfiectins 1.-

ill

2 pulses for causing tens transfer entries to be made in an accumulator, when required, and in such a manner as not to interfere with the normal digital entries in the accumulator.

It is an object of this invention to provide an impulse generating apparatus which is capable of producing output impulses simultaneously on a plurality of output conductors and which requires but a minimum of components.

A furtherobject of the invention is to provide a low impedance source of impulses which can produce strong impulses whose quality will not be impaired when they are switched simultaneously to a plurality of denominational output conductors.

With these and incidental objects View, the invention includes certain novel features of construction and combinations of parts, a preferred form or embodiment of which is hereinafter described with reference to the drawings which accompany and form a part of this specification.

Of the drawings:

Figs. l-A and 1B together show a circuit diagram of an impulse generator and the controls therefor.

In order that the invention may be explained more fully, a preferred embodiment of the invention will be described, in which description values of potential and circuit elements, such as resistors and capacitors, will be given and types of tubes will be specified. It is not intended, however, to limit the invention to the embodiment described nor to limit the circuit values and tube types to those specified, because these are merely selected as illustrative. It is obvious that other potentials and/or other similar tube types can be used and the circuit values of resistance and capacitance can be adjusted to maintain the proper relation between the various parts of the circuits. Throughout the circuit diagrams, the heater elements for the tubes are shown conventionally.

Impulse generator The impulse'generator is capable of generating impulse trains containing difierent numbers of impulses corresponding to the digits of the notation in which computations are to be made, and is capable of sending the required number of impulses over one or more output conductors according to the digits desired to be entered into various denominations of an accumulator. The impulse generator and its controls are shown in Figs. 1-.A and 1-13.

A multi-vibrator type oscillator consisting of tubes H and 12 (Fig. l-A) is provided to drive the impulse generator and to coordinate the operation of the tens transfer means of the accumulator with the digit entries. These tubes have their anodes l3 and I4 connected over points 55 and i6 and resistors l1 and [8, of 22,000 ohms each, to conductor 19, which extends to terminal 23, to which a potential of +250 volts is applied. The cathodes 2| and 22 of these tubes are grounded. The grid 23 of tube II is coupled over capacitor 24, of 50 micro-microfarads, to point [B in the anode circuit of tube 12 and also is connected to ground over a l-megohm resistor 25. Similarly, grid 26 of tube I2 is coupled over capacitor 21, of 50 micro-microiarads, to point IS in the anode circuit of tube II and also is connected to ground over resistor 28 of 1 megohm. While tubes H and 12 are shown and function, as two separate tubes, they need not be separate but can be the two sections of a single tube such as may be purchased from Radio Corporation of America under type designation 12AU'7. With the values given, and using the 12AU7 type of tube, the oscillator will oscillate at about 7,500 cycles per second, and points as IE and i6 will make a like number of positive potential excursions.

Point 16 is coupled over a. capacitor 30 of 250 micro-microfarads to grid 3| of a driving impulse generating tube 32. Tube 32, which is shown as a separate tube but which preferably is a half or a twin triode, such as a tube sold by Western Electric Company under the type designation 2051, is normally biased to cut-off by having its grid 3| connected over a resistor 33 of 150,000 ohms and over conductors 34 and 35 to terminal 36, to which 30 volts is applied, and is allowed to conduct momentarily each time the potential of point l6 becomes sufficiently positive in the operation of the oscillator to overcome the negative bias on the grid 3!.

Tube 32 has its anode 31 directly connected to the conductor l9, to which +250 volts is applied, and has its cathode 38 connected to ground by a relatively low impedance circuit including point 39 and resistor 40 of 4,700 ohms.

With the values given, a positive potential impulse will be produced at point 39 each time tube 32 conducts momentarily, and these impulses are used to cause the sequential operation of a chain of priming tubes and to drive the impulse-train-producing tubes.

The chain of priming tubes (Figs. l-A and 1-13) utilizes gaseous tetrodes, such as tubes sold by General Electric Company under type designation GL5663, and includes a start tube and a priming tube for each of the digits 1 through ((9.7!

The start tube (Fig. 1-A) has its anode connected directly to an anode potential supply conductor 46, which normally has a potential of +125 volts supplied thereto from point 41 in the cathode circuit of an extinguishing tube 48.

The control grid 49 of the start tube is normally biased to prevent conduction in the tube by being connected over resistor 50, of 47,000 ohms, point 5|, and resistor 52 of l megohm to terminal 53, to which a potential of -30 volts is applied.

The cathode 60 of the start tube is given a potential slightly more negative than ground when the tube is non-conducting. This potential is obtained by connecting the cathode at point 6| in a resistance-capacitance network extending from point 62 on conductor 63, to which a potential of 108 volts is applied at terminal 64, over resistor 65 of 1.8 megohms, point 53, resistor 61 of 1.6 megohms, point 68, resistor 69 of 15,000 ohms, point 6!, and resistor ll) of 22,000 ohms to ground. Point 68 in this circuit is coupled to ground over a capacitor H of 1,000 micro-microfarads. When conduction occurs in the start tube, its cathode 60 will also be conductively coupled to the anode 45, and its potential will change from slightly negative to positive with respect to ground.

The auxiliary or shield grid I2 of the start tube is connected to the cathode 60 and will have the same potentials as the cathode.

The start tube is the first tube in the chain and is followed by the 3, t, l, 0, 5, 4, 3, 2, and l priming tubes in that order. The circuits for the various priming tubes are similar and will be clear-from an explanation or" the circuits for the 9 priming tube (Fig. l.A).

The anode 15 of the 9 priming tube is con" nected directly to the anode potential supply conductor 46.

The auxiliary or shield grid 16 of the 9 priming tube is connected. over resistor ll of 47,000 ohms, point I8, and resistor 13, of 1 megohm, to negative potential supply conductor 8'3, which is connected to terminal 53 and has a potential of -30 volts applied thereto. The auxiliary grid i8 is also coupled over point 18 and capacitor M of 10 micro. .icroiarads to a driving impulse input conductor 13, which connects over point 4! to point 39 in the cathode circuit for tube 32 and receives a positive driving impulse of about volts each time tube 32 con ducts momentarily.

The control grid ii of the 9 priming tube is connected to point 66 in the cathode potential supply circuit for the start tube and, with the start tube non-conducting, has a normal negative bias sufficient to prevent the 3 priming tube from becoming conducting even though driving impulses are applied to the auxiliary grid. When the start tube has been fired and is conducting, the positive potential of its cathode 55 will be reflected on the potential of the control grid 8| of the 3 priming tube and will reduce the negative bias thereon to a point where the tube can become conducting in response to a driving impulse impressed on its auxiliary grid.

The cathode 32 of the 9 priming tube is supplied with potential from a resistancecapacitance network, like the one for the start tube, which extends to ground from the negative potential supply conductor 53.

Each of the priming tubes for the digits 8 to 1 inclusive has an anode potential supply circuit and a cathode potential supply circuit like those for the 9 priming tube, each has a negative potential supply circuit for its auxiliary or shield grid and capacitance coupling from its auxiliary grid to the driving impulse input conductor 13, similar to those described above in connection with the 9 priming tube, and each has its control grid connected to the cathode potential supply circuit of the preceding tube in the chain to be primed thereby upon conduction occurring in the preceding tube.

It is to be noted that the driving impulses from tube 32 are not effective to cause an unprimed tubeio conduct; consequently the impulses will be ineffective on any of the priming tubes of chain until the start tube has been fired and primes the 9 priming tube. The start tube is fired in the following manner. Point 5! in the control grid circuit for the "start" tube is coupled over'conductor 85, capacitor 06 of 10 micromicrofarads, and point 81 to.- the motor bar or start key switch 80', which is normally open but which can be closed to connect point 01' to'con'ductor 89, which extends to terminal 90-, to which a potential of +250 volts is applied. When the motor bar or start key switch 80 is closed and the +250 volts is applied to capacitor 86, a positive impulse will be impressed on. the control grid 49', which impulse is sufllcient to fire the start" tube, thereby priming-or conditioning the "9" priming tube so that it can rcspend and be fired by the next driving: impulse on conductor 13. Point 81 in. the motorlbar or start key control circuit is connected to ground over resistor 95 of. 47,000 ohms to provide a discharge path through which capacitor 86' can be discharged when the motor: bar'or start key switch 88 is opened.

Each-. oi the priming tubes, when fired, will prime the next tubeof the chain, so that it will be fired by the next driving impulse. Accordingly, after the "start" tube has been fired by" the closing of the start key switch 88-,- the next nine driving impulses will fire the tubes of thepriming chain one after another;

The tubes of the chain, being gas tubes, will remain conducting, once they are fired, until they are extinguished by the operation of an extinguishing means which includes the tube 481 This operation of the extinguishing means takes place after the last tube in the chain has been fired and has. eif'ected its control, atwhich time all the tubes of the chain are rendered nonconducting.

Since the priming tubes of the chain are firedin sequence by successive driving impulses and are allextinguished at the same time, the several tubes will be conducting for progressively longer periods of time; that isr the 9 priming tube will be conducting longer" than the tube, the 0" tube will be conducting longer than the T tube, etc.

Each priming" tube controls a'related impulsetrain-producing tube by priming that tube as long as the primingtube is conducting, and enables the driving impulses from tube 32, which are impressedcontinuously on the impulsetrain-producing tubes; to become efi'ective to operatethe tube and produce a train of impulses corresponding in number to the digit to which the priming tube is related. For example, the impulse-train-producing tube related to the "9 priming tube will produce a train containing nine impulses, the impulse-train-producing tube which is related to the "'8" priming tube will. produce a train of eight impulses, etc, the impulse-train-produc'in'g' tube related tothe I priming tube producing one impulse.

The circuits and controls for the impulsetrai'n-producing tubes are similar, and it is believed that an understanding of the operation 0! all these tubes willbe clear from a descriptlon of the operation of one: of them.

The impulse-train-producing tube for producing a train of nine impulses is representative and is shown at I00 in Fig. 1-5. This tube is shown as a separate trio'de, but preferably it is one half of a twin triode, such as the abovementioned 2651 type of tube. The tube has its anode I0l connected directly to conductor Ii, which, as explained earlier herein, has a potential of +250- voltsapplicd thereto at termiinal 20. The cathode I02 of the tube is connected over point I03 and resistor I04 of 2,200 ohms to point I05 on potential supply conductor I06, which has a potential 01' volts applied thereto at terminal I01. This anode-cathode potential supply circuit has a very low impedance and will produce a strong positive impulse of about 55 volts at point I 03 each time the tube I 00' is operated.

Control grid I09 of tube I00 is connected over point Hi0 and resistor III of 100,000 ohms to point I I2 in the cathode potential supply circuit for the 9 priming tube. Point H0 in the grid circuit is also coupled over a capacitor [[3 of 250 micro-microfarads to the driving impulse input conductor H4, which is connected over point M to point 39 in the circuit of the driving impulse generating tube 32. When thefQ priming tube is not conducting, point H2 in its cathode circuit and consequently grid I00 of the impulse-train-producing tube I00 will be slightly negative with respect to ground, and, since the cathode I02 is at a potential of +130 volts, the tube I00 will be biased sufiiciently past cut-oil that the driving impulses on conductor II4 will be ineffective to cause conduction in tube I00. However, when the 9 priming tube is conducting and its cathode has become positive, point H2 will become more positive and reduce the bias on tube I00 to a point where the driving impulses on conductor II will be eifective to cause momentary conduction in the tube I00 and thereby provide positive impulses at point 03. Capacitor i I5, which is' similar to ca pacitor l! in the cathode circuit of the start tube, delays the application of the priming potential to grid I09 sufliciently that the impulse which fires the 9 priming tube will have passed before the tube I00 is ready for operation. The first driving impulse that will: be effective on tube I00 will be the same one that fires the 8 priming tube.

Conductor I20 is connected to point res and will have the positive impulses at point :83 impressed thereon. Switch i l, which can be close: by a 9 digit key or any other switch-operating device in the units denominational order, will connect the conductor I20 to a units denominational output conductor I22. Similarly, a switch 923 can be closed by a 9 digit or other switchoperating' device in the tens denominational order to connect the conductor 20 to a tens denominational output conductor IE4. While only two sets. of. switches and two denominational output conductors have been shown, it is obvious that as many can be provided as are needed according to the denominational capacity desired.

Each of the other impulse-train-producing tubes has connections similar to the ones given above and is capable of producing. the required number of impulses which can be switched to output conductors I22. and I24 as desire-:1. The use of the low impedance source of impulses allows the impulses to be switched to a plurality of. output conductors without impairing the ability of the impulses to operate the accumulator.

The driving impulse, which follows the driving impulse which fires the I priming tube, will be effective on the primed impulse-train-producing tubes to cause the last impulse in each train to be generated and will be effective the primed tube IE4 (Fig. l-B) to cause that tube to operate and generate the impulse for'eiiecting an entry of the digit 1 in the accumulator. This impulsewhich is: generated by the tube Hie goes out over conductor I45, from which it can be switched to output conductors, as 22 and I24. The impulse on conductor I45 also is used to operate the extinguishing means to cause the tubes of the chain to be extinguished and remove the priming from the impulse-train-producing tubes As explained earlier herein, the anodes of the start tube and the priming tubes I to 9 are connected to conductor 46. The potential of conductor 46 is derived from an impedance network having one branch which extends from point i50 on l08volt conductor 63, over resistor II of 56,000 ohms, point I52, and to ground over resistor E53 of 500,000 ohms, and having another branch which extends from point I52, over point 41, to the cathode I54 of the extinguishing tube 43, and through the tube whose anode I55 is directly connected to conductor 89, to which a potential of +250 volts is applied. Tube 48 is preferably of the type sold by Radio Corporation of America under the type designation GAQS, and, by varying the impedance thereof, the potential applied to conductor 46 and the anodes of the tubes of the chain can be controlled.

Normally, the potential on the control grid I56 of tube 48 is such that the tube will conduct suificiently to give its cathode I54 and the conductor 46 a potential of +125 volts. However, when the potential on the grid I56 of tube 48 is modified to increase the impedance of the tube so that less current flows therethrough, the cathode potential and that of conductor 46 will become less positive and even may become negative with respect to ground, thereby causing the anode potential of the conducting tubes of the chain to drop below their cathode potential and the tubes to be extinguished.

The potential of grid I56 is controlled from a resistor 60 in the anode circuit of a twin triode control tube I6I, which is preferably of the type sold by Radio Corporation of America under the type designation 12AX7. The anodes I62 and I63 are connected together and over the resistor I60 of 470,000 ohms to conductor 89, to which a potential of +250 volts is applied.

The cathode I64 of one of the triodes of tube I6I is connected directly to terminal I65 and has a potential of +65 volts applied thereto. The cathode I66 of the other triode of tube I6I is connected directly to terminal I61, to which a potential of -98 volts is applied.

Grid I cooperates with the anode I63 and the cathode I64 to determine the normal potential applied to grid I56 of tube 48. Grid I10 is supplied with the required potential from an adjusta'ble tap I1I on resistor I53.

Grid I'i2 cooperates with the anode I62 and the cathode I66 of tube I6l and is eiiective therethrough to modify the potential of grid I56 of extinguishing tube 48 to increase the impedance of this tube and cause the extinguishing of the tubes of the chain.

The impulse which is generated by tube I44 and is applied to conductor I45 is impressed on grid I12, either directly or through an impulsewidening device, and will cause the extinguishing of the tubes of the chain. In the disclosed embodiment, the impulse on conductor I45 will be applied through an impulse-widening device. Conductor I45 is coupled through a capacitor I15 of .005 microfarad to the anode I16 of a diode I11. Preferably this diode is one half of a twin diode tube of the type sold by Radio Corporation of America under the type designation 6AL5. Anode I16 of the diode I11 is also connected over resistor I18 of 39,000 ohms and conductor I19 to conductor 63, which has a potential of 108 volts applied thereto. Cathode I of the diode is also connected to conductor I19 over a resistor I8I of 1 megohm in parallel with a capacitor I82 of 250 micro-microfarads. Point I83 is this circuit is connected over resistor I84 of 200,000 ohms to the grid I12 of the control tube.

A positive impulse on conductor I45 will be effective, through the low impedance of the diode I11, to charge capacitor I82 and make point I83 and the grid I12 connected thereto more positive. Since the discharge paths for the capacitor E82 are through the resistor I8l of 1 megohm and the high back impedance of the diode I11, the grid I12 will remain positive for a longer time iilzan that required for the impulse on conductor When grid I12 becomes more positive and more current flows through resistor I60, grid I56 will become more negative and increases the impedance of tube 48, thereby to reduce the anode potential applied to the tubes of the chain sufficiently to cause them to be extinguished.

The impulse-widening means, while not necessary, provides an additional factor of safety in the operation of the device, because it allows the anode potential for the tubes of the chain to be depressed for a longer period of time than required to deionize them and insures that all tubes of the chain will be extinguished.

Accordingly, for each operation of the start tube, impulse-train-producing tube I00 will produce a train of nine impulses on conductor I20; tube I30 will produce a train of eight impulses on conductor I3I; tube I32 will produce a train of seven impulses on conductor I33; tube I34 will produce a train of six impulses on conductor I35; tube I36 will produce a train of five impulses on conductor I31; tube I38 will produce a train of four impulses on conductor I39; tube I40 will produce a train of three impulses on conductor I4I; tube I42 will produce a train of two impulses on conductor I43; and tube I44 will produce an impulse on conductor I45. Each impulse train is common to the plurality of denominational output conductors, and the trains of impulses can be switched to the output conductors according to the digits desired to be entered into the various denominations of the accumulator.

If no entry is to be made in any denominational order of the accumulator, a zero switch, as I46, for that order is closed to connect the related output conductor to conductor I06 over a resistor I41 of 2,200 ohms to provide a comparable low impedance loading for the output conductor when it is not otherwise connected to an impulse-train-producing tube.

It should be noted that the start tube and its controls will allow only one impulse-trainproducing operation of tubes I00, I30, I32, I34, etc., for each closure of the motor bar or key switch 88, because, as long as the switch remains closed, capacitor 86 will remain charged, and no additional firing impulses can be applied to the control grid 49 of the start tube.

The impulse generator also includes a transfer-effecting impulse-generating means which is controlled from the oscillator and is timed to cause transfer entries to be made without interference with digit entries in the accumulator.

, The transfer-effecting impulse-generating tube 9 I90 (Fig. l-A), which preferably is one half of the above-noted 12AU7 type of tube, has its anode I9I connected over point I92 and resistor I93 of 22,000 ohms to conductor I9, to which is applied a potential of +250 volts, and has its cathode I 94 directly connected to ground. Control grid I95 normally biases the tube to cut-off by being connected over resistor I96, point I91, and resistor I98 to conductor 35, to which a potential of 30 volts is applied at terminal 36. Control grid I95 is also coupled from point I 91 over capacitor I99 of 250 micro-microfarads to point I in the anode circuit of tube I I of the oscillator, and will allow the tube I90 to conduct each time the potential of point I5 becomes more positive in ,1

the operation of the oscillator.

Whenever the tube I90 conducts, a negative potential drop of about 150 volts occurs at point I92 in its anode circuit, and these potential drops are applied over conductor 200 (Figs. l-A and l-B) and resistor I of 47,000 ohms to the transfer means of the units denominational order of the accumulator and over resistor 202 of 47,000 ohms to the transfer means of the tens denominational order of the accumulator. The transfer means and the manner in which they are operated by the impulses is fully disclosed in said Patent No. 2,591,007, and will not be described herein. The negative impulses which are impressed on conductor 200 will occur during the intervals between the positive impulse on the denominational output conductors I22 and I24 and are effective to cause transfer entries to be made in the accumulator without interfering with the digit entries.

The impulse generating apparatus described above accordingly uses a minimum of tubes to produce strong impulses simultaneously on a plurality of output conductors. It is to be noted that an increase in the number of output conductors does not cause any increase in the number of tubes required since all that need be added are additional output conductors and corresponding banks of keys for selectively coupling the output conductors to the various conductors I20, I3I, I33, I35, I31, I39, I4I, I43 and I45.

While the form of the invention shown and described herein is admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to confine the invention to the one form or embodiment disclosed herein, for it is susceptible of embodiment of various other forms.

What is claimed is:

1. In an impulse generator, the combination of a plurality of impulse-train-generating electronic devices, one of said devices being provided for each of the digits 9 through 1 and each of the devices having at least a pair of main electrodes and means to control conduction therebetween; a low-impedance operating potential supply circuit for each of said devices, the cir' cuit for each device containing a low impedance in the circuit to one of the main electrodes, across which impedance a strong impulse is generated each time the device operates; means for supplying driving impulses to the conduction con trol means of the plurality of devices; control means coupled to the conduction control means of the devices for normally rendering each of the devices non-responsive to the driving impulses, said control means being operable to render the devices responsive to the number of driving impulses corresponding to the digit which it represents, whereby to produce, at said one of the main electrodes of each device, an impulse train which contains the corresponding number of impulses; a plurality of separate output conductors; and means selectively coupling the output conductors to desired ones of said one main electrodes to enable the desired ones of said impulse trains to be impressed on the conductors, said low-impedance sources for the trains of impulses minimizing cross-talk between output conductors and also generating strong impulses whose quality is not impaired even when they are switched simultaneously to a plurality of output conductors.

2. An impulse generator as claimed in claim 1 in which the control means contains a plurality of gaseous electron tubes, one for each of the digits 1 through 9, each tube containing an anode, a cathode, and means to control conduction therebetween, an operating potential supply circuit for the tubes including an individual resistor in each cathode circuit, cathode-to-conduction control-means connections connecting the tubes in a chain beginning with the 9 tube whereby conduction in a tube can prime the next tube for operation, an input circuit connecting the conduction control means for the several tubes to the driving impulse generating means so that driving impulses will be applied to the tubes and fire the primed tubes one after another in succession, and means to prime the 9 tube; and in which the coupling between the control 'means and the impulse-training-generating devices includes connections from the cathodes or" the tubes to the conduction control means of their related devices whereby the tubes, as they conduct, modify the control by the conduction control means and allow the impulse-train-gencrating devices to respond to the driving impulses.

3. An impulse generator as claimed in claim 2 in which the operating potential supply means for the tubes includes a device coupled to the inlprllse-train-generating device for the digit 1 and operated by the impulse of the 1 digitrepresenting train to modify the operating potential supplied to the tubes to thereby cause any conducting tubes in the control means to be extin-guished.

4. An impulse generator as claimed in claim 1 in which the control means contains a plurality of electronic devices including a start device and a device for each of the digits 1 through 9, and circuits interconnecting the devices in an operative chain beginning with the start device and then the digit devices 9 through 1, said circuits enabling conduction in a device to prepare the nextdeviceior operation; in which the control means contains a circuit connecting the devices for the digits 9 through 1 to the means for supplying driving impulses, said impulses being effective to operate the devices which have been prepared for operation; in which the control means includes means to operate the start device to initiate the sequential operation of the other devices of the chain; in which the. control means includes a resetting device which is operated by the impulse of the impulse train for the digit 1 to restore the devices of the chain to their inoperative condition; and in which the coupling between the control means and the impulse-train-generating devices includes connections betweenthe devices of the chaincorresponding to the various digits and conduction control means of the impulse train devices related to the same digits so that the device of the chain, when operated, can reduce the I bias on the conduction control means of its rell lated impulse-train-generating device and allow the driving impulses to be effective thereon.

5. In an impulse generator, the combination of a plurality of impulse-train-generating electronic devices, one of said devices being provided for each of the digits 9 through 1 and each of the devices having at least a pair of main electrodes and means to control conduction therebetween; a low-impedance operating potential supply circuit for each of said devices, each circuit containing a low impedance in series with one of the main electrodes of its related devices, across which impedance a strong impulse is generated each time the device conducts; means for supplying driving impulses to the conduction control means of the plurality of devices; control means coupled to the conduction control means of the devices and normally effective to render each of the devices non-responsive to said driving impulses; said control means, when operated, being effective to render each of the devices responsive to the number of driving impulses corresponding to the digit which it represents, whereby to produce an impulse-train at said one of the main electrodes which contains the corresponding number of impulses; means to cause the control means to operate; a plurality of denominational output conductors; a plurality of denominational means selectively coupling the output conductors to desired ones of said one main electrodes to enable the impulse-trains containing the desired numbers of impulses to be impressed simultaneously on the conductors; and means operated by the impulse of the impulsetrain for the digit 1 to restore the control means to its unoperated condition to prevent further impulses from being generated by the impulse-train generating devices.

6. In an impulse generator, the combination of a plurality of impulse-train generating devices, one of said devices for each of the digits 9 through 1 and each of the devices having at least a of main electrodes and means to control conduction therebetween; a low-impedance operating potential supply circuit for each of said devices, each circuit containing a low impedance in the circuit to one of the main electrodes of its related device, across which a strong output impulse is generated each time the device conducts; means for supplying driving im pulses to the conduction control means of the plurality of devices; priming means coupled to the conduction control means of the devices and normally effective to render the impulses ineffective thereon, said priming means being operable from a normal condition to prime each of the devices in sequence to render the devices responsive to the number of driving impulses corresponding to the digit which it represents, whereby to produce, at said one of the main electrodes of each device, an impulse-train which contains the corresponding number of impulses; a start device coupled to the priming means, and, when operated, enabling the priming means to operate; a plurality of denominational output conductors; means selectively coupling the output conductors to desired ones of said one main electrode to enable the desired impulse trains selectively to be impressed on the conductors; and restoring means controlled from the impulse-train-generating device for the digit 1 and operable by the impulse representing the digit 1 for restoring the start device and the priming means to their unoperated condition.

'7. In an impulse generator, the combination of a plurality of impulse-train-generating elec tronic devices, one of said devices being provided for each of the digits 9 through 1; an operating potential supply circuit for each of said devices, the circuit for each device containing a separate impedance, across which impedance an impulse is generated each time the device conducts; means for supplying driving impulses; means coupling the means for supplying driving impulses to the plurality of devices to supply driving impulses to the devices; control means coupled to the devices for normally rendering each of the devices non-responsive to the driving impulses, said control means, when operated, controlling the devices to render the devices responsive in succession and for a predetermined time so that each of the devices can respond to the number of driving impulses corresponding to the digit which it represents, whereby to enable each device to produce an impulse train which contains the corresponding number of impulses; means to operate the control means to render the devices responsive in succession; a plurality of separate output conductors; and means simultaneously coupling the output conductors selectively to desired ones of said devices to enable the impulse trains containing the desired numbers of impulses to be impressed on the conductors.

8. In an impulse generator, the combination of a plurality of impulse-train-generating electronic devices, one of said devices being provided for each of the digits 9 through 1; an operating potential supply circuit for each of said devices, the circuit for each device containing a separate impedance, across which impedance an impulse is generated each time the device conducts; means for supplying driving impulses; means coupling the means for supplying driving impulses to the plurality of devices to supply driving impulses to the devices; control means connected to the means for supplying drivin impulses to be operated by driving impulses and coupled to the devices, said control means normally efiective to render the devices non-responsive to the driving impulses but, when driven by the driving impulses, operable to render each of the devices responsive in succession and for a predetermined time to enable each device to respond to the number of driving impulses corresponding to the digit which it represents, whereby to concomitantly produce impulse trains at the several devices which contain the corresponding numbers of impulses; means to initiate an operation of the control means by said driving impulses; a plurality of output conductors; and a plurality of output selector means for coupling the output conductors to desired ones of said devices to enable the impulse trains containing the desired numbers of impulses selectively to be impressed on the conductors.

9. In an impulse generator, the combination of a plurality of impulse-train-generating electronic devices, one of said devices being provided for each of the digits 9 through 1; an operating potential supply circuit for each of said devices, the circuit for each device containing a separate impedance, across which impedance an impulse is generated each time the device conducts; means for supplying driving impulses; means coupling the means for supplying driving impulses to the plurality of devices to supply driving impulses to the devices; control means coupled to the devices and normally effective to render each of the devices non-responsive to the driving impulses, said control means, when operated, controlling the devices to render each device responsive to the number of chi im pulses corresponding to the digit which it represents, whereby to enable each device to produce an impulse train which contains the corresponding number of impulses; means coupling the control means to the means for suppl ing driving impulses to enable the control means to be operated by the driving impulses; a plurality of separate output conductors; and means selec tively coupling the output conductors to desired ones of said devices to enable the i pulse trains containing the desired numbers of impulses to be impressed on the conductors.

10. In an impulse generator, the combination of a plurality of impulse-train-generating electronic devices, one of said devices being provided for each of the digits 9 through 1; an operating potential supply circuit for each of said devices, the circuit for each device containing an impedance, across which impedance an impulse is generated each time the device conducts; means for supplying driving impulses; means coupling the means for supplying driving impulses to the plurality of devices to supply driving impulses to the devices; control means coupled to the devices for normally rendering each of the devices non-responsive to the driv-- ing impulses, said control means, when operated, rendering each device responsive to the number of driving impulses corresponding to the digit which it represents, whereby the various devices operate concomitantly to produce impulse trains which contain the corresponding numbers of 111:. pulses; means connecting the control means to the means for supplying driving impulses to enable the control means to be operated by the driving impulses to render the devices responsive in sequence so that they can respond to the number of driving impulses corresponding to the digits which they represent; a plurality of separate output conductors; and means selectively coupling the output conductors to desired ones of said devices to enable the impulse trains containing the desired numbers of impulses to be simultaneously impressed on the conductors.

11. In an impulse generator, the combination of a plurality of impulse-train-generating electronic devices, one of said devices being provided for each of the digits of a notation and each of the devices having at least a pair of main electrodes and means to control conduction therebetween; an operating potential supply circuit for each of said devices, the circuit for each device containing an impedance in the circuit to one of the main electrodes, across which impedonce a strong impulse is generated each time the related device conducts; means for supplying driving impulses; means coupling the means for supplying driving impulses to the conduction control means of the plurality of devices to supply driving impulses thereto; control means coupled to the conduction control means of the devices for normally rendering each of the devices nonresponsive to the driving impulses, said control means, when operated, controlling the devices to render said devices responsive in succession to further impulses and for a predetermined time, so that each device can respond to the number of impulses corresponding to the digit which it id represents, whereby to produce, at said one of the main electrodes of each device, an impulse train which contains the corresponding number of impulses; means coupling the control means to the means for supplying driving impulses to be operated by the driving impulses to render the devices responsive to the number of driving impulses corresponding to the digit which represents; a plurality of separate output conductors; and means simultaneously coupling the output conductors selectively to desired ones of said one main electrodes to enable impulse trains containthe desired numbers of impulses to be imed on the conductors.

an impulse generator, the combination of a plurali ty cf impulse-train-generating electronic tubes, one of said tubes being provided for each of the digits 9 through 1 and each of the tubes having at least a pair of main electrodes and means to control conduction therebetween; a low-impedance operating potential supply circuit for each of said tubes, the circuit for each tube containing a low impedance in series with one or" the main electrodes of its related tube, across which impedance a strong impulse is generated each time the tube conducts; means for supplying driving impulses; means coupling the conduction control means of the plurality of tubes to the means for supplying driving imto supply driving impulses thereto; control inc-ans connected to the means for supplying driving impulses to be operated thereby and coupled to the conduction control means of the tubes, said control means normally effective to render the tubes non-responsive to the impulses but, when driven by the impulses, operable to render each of the tubes responsive in succession to following driving impulses to enable each tube to respond to the number of driving impulses corresponding to the digit which it represents, whereby to produce an impulse train at said one of the main electrodes which contains the corresponding number of impulses; means to enable the control means to be driven by said driving impulses; a plurality of denominational output conductors; a plurality of denominational rows of keys selectively coupling the output conductors to desired ones of said one main electrodes to enable the impulse trains containing the desired numbers of impulses selectively to be impressed on the conductors; and means operated by the impulse of the impulse train for the digit to restore the control means to its unoperated condition to prevent further impulses from being generated by the impulse-train-generating tubes after the tubes have generated their corresponding numbers of impulses.

CARL F. BENCH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,308,778 Prince Jan. 17, 19 1-3 2,398,771 Compton Apr. 23, 1946 2,404,697 Desch July 23, 1946 2,451,812 Desch et a1 Oct. 19, 194:8 2,503,127 Mumma Apr. 4, 1950 2,575,331 Desch Nov. 2-3, 1951 FOREIGN PATENTS Number Country Date 357,532 Great Britain Sept. 14, 1931 

